A laboratory assessment of the toxic attributes of six 'reduced risk insecticides' on Galendromus occidentalis (Acari: Phytoseiidae)

The modified excised leaf disc method was used to measure the effects of six insecticides on eggs, larvae, adults, and female fecundity of Galendromus occidentalis (Nesbitt) in a ‘worst case laboratory exposure’. This study identified insecticides that would be recommended for tier II field evaluations for an integrated pest management program. Commercially formulated insecticides were applied with a thin-layer chromatography sprayer adjusted to 10.34 kPa (1.5 psi), at the recommended label concentrations in Canada. LC₅₀ values were estimated from aliquots above and below that concentration. Spinetoram and spirotetramat were toxic at label concentrations. The label concentration for spinetoram was 34.3-fold the LC₅₀ estimate (0.006 g L⁻¹) and for spirotetramat the label concentration was 7.7-fold the LC₅₀ estimate (0.03 g L⁻¹). Clothianidin was considerably less toxic and the label concentration was 0.15-fold the LC₅₀ estimate (2.29 g L⁻¹). Estimates of LC₅₀ for novaluron and chlorantraniliprole could not be established. Both materials showed slight toxicity to at least one growth stage of the predator. Novaluron, clothianidin and chlorantraniliprole should be evaluated in the field for compatibility in IPM programs. Flubendiamide was harmless to all growth stages and it is recommended for inclusion in IPM programs without additional tier II field evaluations. Field evaluations with spinetoram and spirotetramat should be pursued only if alternatives are unavailable.     

Detection of advected, reacting redox fronts from self-potential measurements

We report on an experiment aimed at testing the use of self-potential measurements to monitor the motion and mixing of redox reactants advected through a well-controlled, laboratory-scale, artificial aquifer system. A rectangular, plastic tank was filled up with water-saturated sand and an array of unpolarizable electrodes was installed in the sand body. A nearly uniform, steady-state flow was established by tilting the tank and controlling the water level in reservoirs at both ends. Then, we simultaneously injected a known quantity of KMnO(4) and FeCl(2), respectively, into two separate compartments forming the upstream reservoir. We thus generated two abrupt fronts, one oxidizing and the other reducing, which subsequently travelled in parallel by advection through the sand body. The KMnO(4) and FeCl(2) solutions were in contact and reacted with each other in a region located along the median vertical plane parallel to the flow direction. During flow, the electrical potential differences between each electrode and a reference located in the downstream reservoir were recorded. In the unreacted FeCl(2) region the electric potential showed sudden variations successively occurring at increasing distances in the flow direction, associated with the passage of the FeCl(2) front. These signals essentially corresponded to the junction potential produced by the difference in ionic mobility of Fe(2+) and Cl(-). In the unreacted KMnO(4) region sharp signals, but with much smaller amplitudes, were also observed. Near the vertical median plane on the FeCl(2) side, we observed a second front associated with the spreading of the reaction zone. The shape and evolution of the reaction zone was largely controlled by the precipitation of Fe(OH)(3).     

Impact of peri-urban landscape on the organic and mineral contamination of pond waters and related risk assessment

Environmental Science and Pollution Research - Ponds are important for their ecological value and for the ecosystem services they provide to human societies, but they are strongly affected by human...     

The use of fetal MRI for renal and urogenital tract anomalies

Fetal anomalies are detected in approximately 2% of all fetuses and, among these, genitourinary tract abnormalities account for 30% to 50% of all structural anomalies present at birth. Although ultrasound remains the first line diagnostic modality, fetal MRI provides important additional structural and functional information, especially with the development of faster sequences and the use of functional sequences. The added value of MRI-based imaging is three-fold: (a) improvement of diagnostic accuracy by adequate morphological examination, (b) detection of additional anomalies, and (c) in addition, MRI has the potential to provide information regarding renal function. In this review, we describe the role of fetal MRI in the anatomical evaluation of renal and urogenital tract anomalies, and we also touch upon the contribution of functional MRI to the diagnostic workup of these conditions.     

Documentation of the endotoxins present in the ambient air of cotton fiber textile mills in Québec

Cotton workers are recognized as being at risk of developing occupational lung diseases. Some researchers have identified endotoxins as being a potential etiologic agent for some of the respiratory problems. This study wants to document the concentration of endotoxins found in the ambient air of textile mills where cotton fibers are handled and to identify the processing steps where the highest endotoxins concentrations in the air were found and the one where the relative limit values (RLVs) are exceeded. The 4 mills studied process cotton fibers. All the air samples were analyzed using the chromogenic Limulus Amoebocytes lysate LAL method using a kinetic detection principle based on the IRSST's standard method. In this study, a large variability in the concentrations of endotoxins in the air was observed, depending on the mill, the processing step, and the time. Despite these variations, some processes can be identified as being major generators of endotoxins in the ambient air of the mills. The highest concentrations were measured in the weaving and drawing processes and reached 10,000 EU m(-3) of air. The opening, cleaning, carding, spinning and drawing processes are the other major endotoxins generating processes with concentrations from 24 to 8,700 EU m(-3) of air. The endotoxins concentrations exceeded the RLVs for 55% of the workstations in this project. This study demonstrated that endotoxins levels in the cotton industry are high and appropriate control measures are needed.